1 // Copyright (c) 2011-present, Facebook, Inc. All rights reserved. 2 // This source code is licensed under both the GPLv2 (found in the 3 // COPYING file in the root directory) and Apache 2.0 License 4 // (found in the LICENSE.Apache file in the root directory). 5 // 6 // Copyright (c) 2011 The LevelDB Authors. All rights reserved. 7 // Use of this source code is governed by a BSD-style license that can be 8 // found in the LICENSE file. See the AUTHORS file for names of contributors. 9 10 #include "table/block_based/data_block_footer.h" 11 12 #include "rocksdb/table.h" 13 14 namespace ROCKSDB_NAMESPACE { 15 16 const int kDataBlockIndexTypeBitShift = 31; 17 18 // 0x7FFFFFFF 19 const uint32_t kMaxNumRestarts = (1u << kDataBlockIndexTypeBitShift) - 1u; 20 21 // 0x7FFFFFFF 22 const uint32_t kNumRestartsMask = (1u << kDataBlockIndexTypeBitShift) - 1u; 23 PackIndexTypeAndNumRestarts(BlockBasedTableOptions::DataBlockIndexType index_type,uint32_t num_restarts)24uint32_t PackIndexTypeAndNumRestarts( 25 BlockBasedTableOptions::DataBlockIndexType index_type, 26 uint32_t num_restarts) { 27 if (num_restarts > kMaxNumRestarts) { 28 assert(0); // mute travis "unused" warning 29 } 30 31 uint32_t block_footer = num_restarts; 32 if (index_type == BlockBasedTableOptions::kDataBlockBinaryAndHash) { 33 block_footer |= 1u << kDataBlockIndexTypeBitShift; 34 } else if (index_type != BlockBasedTableOptions::kDataBlockBinarySearch) { 35 assert(0); 36 } 37 38 return block_footer; 39 } 40 UnPackIndexTypeAndNumRestarts(uint32_t block_footer,BlockBasedTableOptions::DataBlockIndexType * index_type,uint32_t * num_restarts)41void UnPackIndexTypeAndNumRestarts( 42 uint32_t block_footer, 43 BlockBasedTableOptions::DataBlockIndexType* index_type, 44 uint32_t* num_restarts) { 45 if (index_type) { 46 if (block_footer & 1u << kDataBlockIndexTypeBitShift) { 47 *index_type = BlockBasedTableOptions::kDataBlockBinaryAndHash; 48 } else { 49 *index_type = BlockBasedTableOptions::kDataBlockBinarySearch; 50 } 51 } 52 53 if (num_restarts) { 54 *num_restarts = block_footer & kNumRestartsMask; 55 assert(*num_restarts <= kMaxNumRestarts); 56 } 57 } 58 59 } // namespace ROCKSDB_NAMESPACE 60